Device for controlling carburetorthrottle closing



1956 c. H. JORGENSEN, JR 2,759,698

DEVICE FOR CONTROLLING CARBURETOR-THROTTLE CLOSING Filed Sept. 25, 1950TTO/P/VE 75.

2,759,698 Patented Aug. 21, 1956 DEVICE FOR CONTROLLING CARBURETOR-THROTTLE CLOSING Clarence H. Jorgensen, .1112, East Rochester, N. Y.Application September 23, 1950, Serial No. 186,439 Claims. (Cl. 251-48)This invention relates to the control of mixture-supply to an automobileengine, particularly to the engine of an automobile equipped with anautomatic transmission. It has been noted that in certain types ofautomobiles equipped with automatic transmissions a sudden opening ofthe throttle followed immediately by an abrupt closing of the throttlewill frequently cause the engine to stop. I have discovered that suchstopping of the engine probably has the following explanation: Thesudden opening of the throttle is accompanied by the supply of excessfuel to the induction passage in anticipation of the fuel demandsincident to acceleration; before this fuel reaches the engine, theabrupt closing of the throttle greatly reduces the rate of air-supply;and the engine stops as a result of over-enrichment of the mixturesupplied to it. At least, I have found that stopping of the engine underthe conditions noted can be eliminated by retarding throttle-closing,particularly in its last stages.

It is therefore an object of this invention to produce a carburetor inwhich it will be impossible to effect an abrupt and complete closing ofthe throttle. Another object of the invention is to provide forincorporation in the throttle-controlling mechanism of the carburetor adevice which, without interfering with the opening movement of thethrottle at any stage of throttle adjustment and without interferingwith the closing movement of the throttle throughout the greater portionof the range of throttle-closing movement, will still prevent an abruptand complete closing of the throttle. Another object of the invention isto produce a simple and inexpensive device which can be applied to acarburetor of standard construction to retard the last stages ofthrottle-closing movement.

The throttles of internal combustion engines are commonly biased towardclosed position and arranged to be moved away from closed position underthe control of an accelerator pedal or other manually operable controlmember. In embodying my invention in association with such carburetor, Iincorporate in the throttle-control mechanism a small dash-pot whichbecomes effective only as the throttle approaches closed position andlimits its continued closing movement under the influence of the biasingmeans. The dash-pot mechanism is conveniently mounted in associationwith the idle adjustment of the carburetor and, in one form of theapplication, may replace the customary idle-adjustment screw.

The accompanying drawing illustrates the invention: Fig. 1 is anelevation of a carburetor in which dash-pot mechanism embodying myinvention has replaced the customary idle-adjustment screw; Fig. 2 is anaxial section through the dash-pot mechanism employed in Fig. 1; Figs. 3and 4 are fragmental views similar to Fig. 1 illustrating modificationsof the invention.

The carburetor illustrated in the drawing, except for its incorporationof my invention, is of a standard type, having a choke valve and athrottle 11. The throttle 11 is mounted on a shaft 12 which, exteriorlyof the carburetor, carries a rigid operating arm 13 connected to anydesired form of throttle-controlling mechanism 14 including a spring 15which biases the arm 13 in the throttle-closing direction. The arm 13carries an extension 16 normally serving as a support for anidle-adjustment screw cooperating with an abutment 17 to limit closingof the throttle. As shown, the abutment 17 is carried by an arm 18forming part of a fast idle device adapted to prevent complete closingof the throttle 11 when the choke 10 is closed.

The dash-pot mechanism employed in the construction shown in Fig. l isillustrated in detail in Fig. 2. It comcable piston prises a cylinder 20having at one end screw-threaded shank or stem 21 adapted to be receivedin the arm-extension 16 in place of the customary idleadjustment screw.Within the cylinder 20 is a recipro- 22 secured to a retarder in theform of a rod 23 which extends axially through the stem 21 and projectsbeyond the end thereof. A spring 24 located within the cylinder 20 urgesthe piston to the right, or in a direction to increase the extent towhich the rod 23 projects from the stem 21. Air displaced by leftwardmovement of the piston escapes through a vent opening 25 controlled byan adjustable needle valve 26.

In embodying my invention in a carburetor, the customary idle-adjustmentscrew may be removed from the an axially projecting arm 16 and thescrew-threaded shank 21 of the dash-pot 20 screwed into the arm 16 toreplace such screw. The dash-pot spring 24 is designed to be much toolight to overcome the spring 15; and, as a result, if the acceleratorpedal is elevated the spring 15 will urge the arm 13 and throttle shaftin the clockwise, or throttle-closing, direction while the rod 23 byreason of its engagement with the abutment 17, will be moved to the leftin the cylinder 20, carrying the piston 22 with it. The completelyclosed, or idling, position of the throttle will therefore be determinedeither by engagement of the end of the cylinder-shank with the abutment17 or by engagement of the piston 22 with the outer end of the cylinder20. In Fig. l, and also in full lines in Fig; 2, the rod 23 is shown asshort enough that its outer end may coincide with the shank 21 beforethe piston engages the outer end of the cylinder; but it will be obviousthat if the rod 23 were longer, the piston would engage the outercylinder end while the rod still projected beyond the end of the shank.In either event, the idling position of the throttle can be varied byadjustment of the screw-threaded shank 21 in the arm-extension 16; andby opening or closing the valve 26, the final stages of throttle-closingmovement may be retarded to the extent desired. The most desirablesetting of the valve 26 is that which will retard throttleclosing onlyto the extent necessary to insure against undue enrichment of themixture under the peculiar circumstances noted earlier in thisapplication. If the accelerator pedal is depressed to open the throttle,the spring 24 acts to move the piston 22 to the right and extend the rod23, the dash-pot mechanism being designed to impose no substantialopposition to such rod-extension. Upon a subsequent closing of thethrottle, the rod 23 engages the abutment 17 as the throttle nearsclosed position, and continued closing movement of the throttle forcesthe rod 23 and piston 22 to the left relative to the cylinder 22. Suchmovement of the piston causes air to be expelled from the cylinderthrough the opening 25.

The modified form of the invention shown in Fig. 3 is adapted for use insituations where clearance conditions are such as to interfere withmovement of the dash-pot cylinder 20 to the open-throttle, dotted-lineposition shown in Fig. 1. In such a situation, the customary idleadjustment screw (shown at 30), is retained in the arm-extension 16, andthe dash-pot 20 is supported from the body of the carburetor on theopposite side of the abutment 17 from the idle-adjustment screw. Theabutment 17 is provid'ed with a slot 31 through which the piston rod 23of the dash-pot may extend into a position such that it will be engagedby the idle adjustment screw 30 as the throttle approaches closedposition. The slot 31 has a width less than the diameter of the screw30, so that the abutment 17 can exercise its normal function by engagingthe end of the screw 30 to limit throttle closing.

The device shown in Fig. 3 operates in substantially the same way asdoes that shown in Fig. 1. With the throttle in an open position, asindicated by the dottedline position shown for the arm 13, the spring 24within the dash-pot cylinder causes the rod .23 to extend through theslot 31 into the path of movement of the end of the adjustment screw 30.As the throttle nears closed position, the adjustment screw 30 engagesthe end :of the rod 23, and closing movement of the throttle is thenretarded by the dash-potaction, as before.

In the modification of Fig. 4, the threaded cylinder shank 21 isreceived in a stationary bracket 35 in such a position that the pistonrod 23 may project through a slot in the car 17 for engagement with anabutment 36 on the throttle-arm 13. This structure functions much thesame as that shown in Fig. 3, except that adjustment is provided byrotating the cylinder to advance or retract it in its screw-threadedmounting in the bracket 35. Closing movement of the throttle may belimited either by the dash-pot or by engagement of the abutment 36 withthe ear 17.

In all the structures illustrated, the dash-pot cooperates either withthe fast-idle lever 18 or with the throttlearm abutment engageable withthat lever. It is to be understood, however, that the dash-pot, whenstationarily mounted, may be associated with any element which moveswith the throttle and, when mounted to move with the throttle, maycooperate with any appropriate abutment.

I claim as my invention:

1. In a carburetor having a throttle and a member movable therewith, .afirst yielding means biasing the throttle toward closed position, adash-pot having a cylinder, a piston, and a piston rod, means mountingthe dash-pot on the member with the piston rod projecting from thecylinder in the direction of throttle-closing movement of the member, anabutment positioned .to engage the outer end of the piston rod as .thethrottle nears closed position, and a second yielding means urging thepiston rod toward said abutment, the dash-pot being so constructed andarranged as to retard throttle-closing movement under the influence ofsaid first yielding means after the piston rod has engaged the abutment.

2. The invention set forth in claim 1 with the addition that saidmounting means is adjustable to vary the point in the throttle-closingmovement at which the piston rod engages the abutment.

3. In a carburetor having a throttle and a member movable therewith, afirst yielding means biasing the throttle toward closed position, anabutment, a retarder carried by said member and movable toward saidabutment by throttle-closing movement of said member and away from saidabutment by throttle-opening movement of the member, said retarder beingmovable relatively to said member toward and away from the abutment, asecond yielding means acting between the member and retarder and urgingthe latter toward the abutment, and retarding means acting between themember and retarder for retarding throttle-closing movement of themember under the influence of said first yielding means after theretarder has engaged the first abutment.

4. In a carburetor having a throttle and a member movable therewith,yielding means biasing the throttle toward closed position, a firstabutment movable with said member, a second abutment engageable by saidfirstabutment to limit throttle-closing movement of said member, anddash-pot means mounted on said member including a movable retarderengageable with said second abutment as the throttle nears closedposition for controlling the rate at which said abutments approach eachother under the influence of said yielding means.

5. The invention set forth in claim 4 with the addition that saiddash-pot means is adjustably mounted on said member to vary the point inthrottle-closing movement at which the retarder engages the secondabutment.

References Cited in the file of this patent UNITED STATES PATENTS2,033,396 Perrine Mar. 10, 1936 2,117,421 Holden May 17, 1938 2,130,915Whisler Sept. 20, 1938 2,166,866 Hansen July 18, 193.9 2,314,570 BallMar. 23, .1943

